Abstract:

A composition comprising particles with a transition metal imbedded
therein is disclosed. Specifically, the ratio of particles to the
transition metal is from about 25:1 to about 50:1. The composition is
prepared in the presence of ultrasonic energy. The particles are selected
from the group consisting of organic particles, inorganic particles, and
metal particles.

Claims:

1. A composition comprising particles with a transition metal imbedded
therein, wherein the ratio of particles to the transition metal is from
about 25:1 to about 50:1, wherein the composition is prepared in the
presence of ultrasonic energy, and wherein the particles are selected
from the group consisting of organic particles, inorganic particles, and
metal particles.

2. The composition of claim 1, wherein the particles are inorganic
particles selected from the group consisting of silica particles and
alumina particles.

3. The composition of claim 2, wherein the particles are silica particles.

4. The composition of claim 1, wherein the transition metal is selected
from the group consisting of scandium, titanium, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, zinc, silver, and gold.

5. The composition of claim 1, wherein the transition metal is copper.

6. The composition of claim 1, wherein the particles with the transition
metal imbedded therein are for removing an odorous compound from a liquid
or gas by chemical adsorption.

7. A composition comprising particles with a transition metal imbedded
therein, wherein the particles are selected from the group consisting of
organic particles, inorganic particles, and metal particles, and wherein
the composition is prepared by a process comprising:providing a treatment
chamber comprising an interior space and an elongate ultrasonic waveguide
assembly positioned within the interior space;delivering a first
formulation into the interior space of the chamber;delivering a second
formulation separately from the first formulation into the interior space
of the chamber;ultrasonically mixing the first and second formulations
via the elongate ultrasonic waveguide assembly operating in a
predetermined ultrasonic frequency.

8. The composition as set forth in claim 7, wherein the first formulation
comprises a basic buffer system.

9. The composition as set forth in claim 8, wherein the basic buffer
system is selected from the group consisting of aqueous sodium
bicarbonate, potassium hydroxide, sodium hydroxide, ammonium hydroxide,
sodium carbonate, and combinations thereof.

10. The composition as set forth in claim 8, wherein the first formulation
is delivered into the interior space of the chamber at a rate of from
about 0.1 grams per minute to about 100,000 grams per minute.

11. The composition as set forth in claim 7, wherein the second
formulation comprises a salt of a transition metal and particles, wherein
the particles are selected from the group consisting of organic
particles, inorganic particles, and metal particles.

12. The composition as set forth in claim 11, wherein the second
formulation is delivered to the interior space of the chamber such that
the particles of the second formulation are present in an amount of at
least about 4% (by weight of the second formulation).

13. The composition as set forth in claim 11, wherein the second
formulation is delivered to the interior space of the chamber at a rate
of from about 0.0001 L/min to about 100 L/min.

14. The composition as set forth in claim 11, wherein the transition metal
is selected from the group consisting of scandium, titanium, vanadium,
chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, and
gold.

15. The composition of claim 11, wherein the transition metal is copper.

16. The composition of claim 7, wherein the particles with the transition
metal imbedded therein are for removing an odorous compound from a liquid
or gas by chemical adsorption.

17. A composition comprising particles with a transition metal imbedded
therein, wherein the particles with the transition metal imbedded therein
are for removing an odorous compound from a liquid or gas by chemical
adsorption, and wherein the particles are selected from the group
comprising organic particles, inorganic particles, and metal particles.

18. The composition of claim 17, wherein the transition metal is selected
from the group consisting of scandium, titanium, vanadium, chromium,
manganese, iron, cobalt, nickel, copper, zinc, silver, and gold.

19. The composition of claim 17, wherein the transition metal is copper.

20. The composition of claim 17, wherein the ratio particles to the
transition metal is from about 25:1 to about 50:1.

Description:

FIELD OF DISCLOSURE

[0001]The present disclosure relates generally to metal-modified silica
particles and methods for preparing metal-modified silica nano-particles.
More particularly, methods for ultrasonically mixing a first and second
formulation using an ultrasonic mixing system to prepare metal-modified
silica particles are disclosed.

BACKGROUND OF DISCLOSURE

[0002]At least some known currently used odor control technologies are
prepared by chemically depositing transition metal layers onto the
surface of silica nano-particles. For instance, U.S. Patent Pub. No,
2005/0084438 to Do, et al., describes modifying the surface of silica
particles with a transition metal so that the silica particles are bonded
to the transition metal through a covalent or coordinate bond. Further,
U.S. Patent Pub. No. 2006/0008442 to MacDonald, et al. describes modified
nano-particles that have active sites that bind various gases and/or
odorous compounds, thereby removing these compounds from a medium such as
air or water. The metal ions are absorbed onto the surface of the
nano-particle and bound strongly to the surface. These modified
nano-particles may be applied to nonwoven webs to provide odor removing
articles for industrial and consumer use. Although these modified
nano-particles are useful, current procedures for forming these
nano-particles have multiple problems, which can waste time, energy, and
money for manufacturers of these modified nano-particles.

[0003]Specifically, synthesis of this technology is sensitive to reagent
concentration, as aggregation and gelation in the reaction suspension may
be observed at silica nano-particle concentrations above 4% (wt/wt). With
this constraint, manufacturing and processing of the technology at the
production scale entails higher costs due to more energy expensed to
remove higher volumes of solvent. Additionally, more substrate material
is needed in order to incorporate higher loading of technology into the
product for increased odor removal efficacy. Particle agglomeration, also
referred to herein as gelation, may be driven by a strong ionic strength
nature in the reaction media due to the chemicals in that media.

[0004]Further, modified nano-particles formed by a stirred suspension of
silica particles and copper salts with a base that is slowly added
results in the active metal complex being formed on the surface of the
silica in discrete zones or nodes. It has been discovered that the
modified nano-particles formed by this method are capable of converting,
for example, thiols (mercaptans) odors into disulphides. The human nose
is particularly sensitive to these odors and can detect the presence of
thiol odors down to part-per-billion (ppb). The human nose's ability to
detect disulphides, however, is significantly less, in fact around tens
of parts-per-million (ppm). Thus, the modified nano-particles may convert
the malodor into a compound that can only be detected at significantly
higher levels and therefore effectively converts the odor into something
the human nose cannot detect. The modified nano-particles could perform
this catalytic conversion continuously for an extended period of time.

[0005]Once the modified nano-particles are formed, three major mechanisms
are involved in remediation of odor compounds: (1) physical adsorption;
(2) catalysis; and (3) chemical absorption. Physical adsorption is the
main pathway by which activated carbon material function. The advantages
of this mechanism include rate and capacity effectiveness, however, the
adsorption can be reversed at changes in temperature or humidity.
Catalysis involves the conversion of an odor compound to another
compound. Ideally, the converted compound should be heavier and posses a
higher boiling point and/or a lower vapor pressure, thus not allowing it
to be re-emitted into the atmosphere. This is not guaranteed or
predictable, however, and may lead to disadvantages compared to something
that is more irreversible. Chemical absorption involves the chemical
binding of the odor compound to the odor removal compound. Typically, the
binding is irreversible when subject to physical challenges such as
temperature and humidity. It has been shown that odorous compounds are
removed from metal-modified silica nano-particles via the catalytic
mechanism when the metal-modified silica nano-particles are prepared
without the presence of ultrasound energy.

[0006]Based on the foregoing, there is a need in the art for a method of
preparing metal-modified silica particles by ultrasonically mixing a
first and second formulation. Furthermore, it would be advantageous if
the system could be configured to enhance the cavitation mechanism of the
ultrasonics, thereby decreasing particle agglomeration and changing the
mechanism by which odorous compounds will be removed during use of the
metal-modified particles.

SUMMARY OF DISCLOSURE

[0007]In one aspect, a method for preparing metal-modified particles by
ultrasonically mixing a first and second formulation comprises providing
a treatment chamber comprising an elongate housing having longitudinally
opposite ends and an interior space. The housing is generally closed at a
first longitudinal end and generally open at a second longitudinal end
for receiving a first and second formulation into the interior space of
the housing, and at least one outlet port through which a
particulate-containing formulation is exhausted from the housing
following ultrasonic mixing of the first and second formulations. The
outlet port is spaced longitudinally from the second longitudinal end
such that liquid (i.e., first and/or second formulations) flows
longitudinally within the interior space of the housing from the second
longitudinal end to the outlet port. In one embodiment, the housing
includes more than two separate ports for receiving additional
formulations to be mixed to prepare the metal-modified particles. At
least one elongate ultrasonic waveguide assembly extends longitudinally
within the interior space of the housing and is operable at a
predetermined ultrasonic frequency to ultrasonically energize and mix the
first and second formulations (and any additional formulations) flowing
within the housing.

[0008]The waveguide assembly generally comprises an elongate ultrasonic
horn disposed at least in part intermediate the second longitudinal end
and the outlet port of the housing and has an outer surface located for
contact with the first and second formulations flowing within the housing
from the second longitudinal end to the outlet port. A plurality of
discrete agitating members are in contact with and extend transversely
outward from the outer surface of the horn intermediate the second
longitudinal end and the outlet port in longitudinally spaced
relationship with each other. The agitating members and the horn are
constructed and arranged for dynamic motion of the agitating members
relative to the horn upon ultrasonic vibration of the horn at the
predetermined frequency and to operate in an ultrasonic cavitation mode
of the agitating members corresponding to the predetermined frequency and
the first and second formulations being mixed within the chamber.

[0009]As such, the present disclosure is directed to a method for
preparing metal-modified particles. The method comprises providing a
treatment chamber comprising an elongate housing having longitudinally
opposite ends and an interior space, and an elongate ultrasonic waveguide
assembly extending longitudinally within the interior space of the
housing and being operable at a predetermined ultrasonic frequency to
ultrasonically energize and mix a first and a second formulation flowing
within the housing to prepare the metal-modified particles. The housing
is closed at a first longitudinal end and open at a second longitudinal
end for receiving a first and second formulation into the interior space
of the housing, and at least one outlet port through which a
particulate-containing formulation is exhausted from the housing
following ultrasonic mixing of the first and second formulations. The
outlet port is spaced longitudinally from the second longitudinal end
such that the first and second formulations flow longitudinally within
the interior space of the housing from the second longitudinal end to the
outlet port.

[0010]The waveguide assembly comprises an elongate ultrasonic horn
disposed at least in part intermediate the second longitudinal end and
the outlet port of the housing and having an outer surface located for
contact with the first and second formulations flowing within the housing
from the second longitudinal end to the outlet port. Additionally, the
waveguide assembly comprises a plurality of discrete agitating members in
contact with and extending transversely outward from the outer surface of
the horn intermediate the second longitudinal end and the outlet port in
longitudinally spaced relationship with each other. The agitating members
and the horn are constructed and arranged for dynamic motion of the
agitating members relative to the horn upon ultrasonic vibration of the
horn at the predetermined frequency and to operate in an ultrasonic
cavitation mode of the agitating members corresponding to the
predetermined frequency and the first and second formulations being mixed
in the chamber.

[0011]The method further includes delivering the second formulation via
the first inlet port into the interior space of the housing, delivering
the second formulation via the second inlet port into the interior space
of the housing, and ultrasonically mixing the first and second
formulations via the elongate ultrasonic waveguide assembly operating in
the predetermined ultrasonic frequency.

[0012]The present invention is further directed to a method for preparing
metal-modified particles. The method comprises providing a treatment
chamber comprising an elongate housing having longitudinally opposite
ends and an interior space, and an elongate ultrasonic waveguide assembly
extending longitudinally within the interior space of the housing and
being operable at a predetermined ultrasonic frequency to ultrasonically
energize and mix a first and second formulation flowing within the
housing. The housing is generally closed at least one of its longitudinal
ends and has at least a first inlet port for receiving the first
formulation into the interior space of the housing, and a second inlet
port for receiving the second formulation into the interior space of the
housing, and at least one outlet port through which a
particulate-containing formulation is exhausted from the housing
following ultrasonic mixing of the first and second formulations. The
outlet port is spaced longitudinally from the first and second inlet
ports such that the first and second formulations flow longitudinally
within the interior space of the housing from the first and second inlet
ports to the outlet port.

[0013]The waveguide assembly comprises an elongate ultrasonic horn
disposed at least in part intermediate the first and second inlet ports
and the outlet port of the housing and having an outer surface located
for contact with the first and second formulations flowing within the
housing from the first and second inlet ports to the outlet port; a
plurality of discrete agitating members in contact with and extending
transversely outward from the outer surface of the horn intermediate the
first and second inlet ports and the outlet port in longitudinally spaced
relationship with each other; and a baffle assembly disposed within the
interior space of the housing and extending at least in part transversely
inward from the housing toward the horn to direct longitudinally flowing
first and second formulations in the housing to flow transversely inward
into contact with the agitating members. The agitating members and the
horn are constructed and arranged for dynamic motion of the agitating
members relative to the horn upon ultrasonic vibration of the horn at the
predetermined frequency and to operate in an ultrasonic cavitation mode
of the agitating members corresponding to the predetermined frequency and
the first and second formulations being mixed in the chamber.

[0014]The method further comprises delivering the first formulation via
the first inlet port into the interior space of the housing, delivering
the second formulation via the second inlet port into the interior space
of the housing, and ultrasonically mixing the first and second
formulations via the elongate ultrasonic waveguide assembly operating in
the predetermined ultrasonic frequency.

[0015]The present disclosure is further directed to a method for reducing
odor using an ultrasonic mixing system as is described above. The method
comprises preparing metal-modified silica particles, isolating the
metal-modified silica particles, and contacting the metal modified silica
particles to an odorous compound.

[0016]Other features of the present disclosure will be in part apparent
and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic of an ultrasonic mixing system according to a
first embodiment of the present disclosure for preparing metal-modified
silica particles.

[0018]FIG. 2 is a schematic of an ultrasonic mixing system according to a
second embodiment of the present disclosure for preparing metal-modified
silica particles.

[0019]FIG. 3 is a schematic of an ultrasonic mixing system according to a
third embodiment of the present disclosure for preparing metal-modified
silica particles.

[0020]FIG. 4 depicts a graph showing ethyl mercaptan removal over time as
described in Example 1.

[0021]FIG. 5 depicts a graph showing remediation of ethyl mercaptan over
time as described in Example 5.

[0031]With particular reference now to FIG. 1, in one embodiment, an
ultrasonic mixing system, generally indicated at 121, for mixing a first
and second formulation to prepare metal-modified particles generally
comprises a treatment chamber, indicated at 151, that is operable to
ultrasonically mix various formulations to form metal-modified particles,
and further is capable of creating a cavitation mode that allows for
better mixing within the housing of the chamber 151. By ultrasonically
mixing the first and second formulations, agglomeration of the silica
nano-particles can be significantly reduced, and the mechanism by which
metal-modified silica particles remove odorous compounds is changed.

[0032]More specifically, by exposing the first and second formulations to
ultrasonic energy, a number of factors take advantage of the unique
sonochemistry and cavitation activities occurring within the mixture
during passage through the chamber that is being mixed by the baffles.
While the elemental composition of the metal-modified silica particles is
the same as a solution deposition system, it differs in numerous physical
and performance characteristics. First, with regard to physical
characteristics, the metal is not merely deposited on the surface of the
silica particle but rather is imbedded below the subsurface of the
particle. Analytically, no trace of the metal can be detected on the
surface. Further, the surface area of the particles is higher than that
of a solution deposition method system. This is due to small pothole-like
holes etched into the surface of the silica particles. In addition, with
regard to performance characteristics, the metal species does not have
catalytic functionality, but rather, has straight absorption of malodor
compounds. Thus, this composition absorbs thiol (mercaptan) odor
molecules and locks them into a complex. Although this composition does
eventually reach a saturation point, which is in contrast to the solution
deposition composition, these metal-modified particles are still a very
effective odor/malodor absorbent. As such, it can be concluded that a
different type of metal complex species has been generated using method
of preparation inclusive of the presence of ultrasonic energy.

[0033]While not fully understood, it is believed that in the ultrasonic
chamber, the metal ions are forcefully imbedded into the sub-surface of
the nano-particles by the extraordinary forces involved in the cavitation
process. The localized high temperatures and pressures may also
contribute to the new metal complex formed therein.

[0034]It is generally believed that as ultrasonic energy is created by the
waveguide assembly, increased cavitation of the formulations occurs,
creating microbubbles. As these microbubbles then collapse, the pressure
within the chamber is increased forcibly dispersing the particles of the
second formulation within and throughout the first and second
formulations.

[0035]More specifically, ultrasonic cavitation is a process by which
extreme pressures, temperatures, and velocities can be generated on a
very small scale for very short periods of time. The mechanism producing
these conditions is the nucleation, growth, and violent collapse of
cavitation "bubbles". These bubbles are formed in several ways when
mechanical pressure waves (alternating compression and rarefaction) are
introduced into a fluid. During the rarefaction phase of the pressure
wave, the liquid molecules are pulled against the liquid's natural
elastic and molecular bonding forces. With sufficient intensity, the
negative pressure can exceed the tensile strength of the liquid and
generate a vacuum nucleus in the liquid. The voids typically form first
at natural "weak" points in the liquid such as entrained gas in the pores
of suspended particulates or small remnant bubbles from previous
cavitation events, however, these are not a requirement. During the
compression phase of the wave, the void collapses.

[0036]Once a bubble is formed, if the expansion phase is fast enough, the
bubble will not be able to fully collapse and it will continue to grow
until it reaches a size described as the resonant point (in water, 170
microns at 20 kHz). At this size, the bubble can efficiently absorb the
ultrasound energy, and the bubble grows rapidly until it reaches a size
where the efficient absorption diminishes and the bubble violently
collapses.

[0037]Another means by which bubble growth occurs at a slower pace is
described as "rectified diffusion". A small gas bubble grows during the
rarefaction phase of the mechanical pressure wave and gas begins to
diffuse into the bubble from the liquid. As the bubble begins to shrink
during the compression phase of the mechanical pressure wave, gas begins
to diffuse out of the bubble back into the liquid. The rate of diffusion
is directly related to the surface area of the bubble. On average, the
bubble surface area is smaller during the compression phase than it is
during the expansion phase. Therefore, more gas diffuses into the bubble
than can diffuse out so the oscillating bubble grows. Once a critical
size is reached, the process can no longer sustain itself and the bubble
collapses.

[0038]In either situation, the violent collapse results in the rapid (much
less than a microsecond) compression of the gas to a pressure of about
1,000 atmospheres resulting in a temperature increase of about
5000° C. The shock waves produced by the numerous cavitation
events result in extremely turbulent micro-mixing and high-speed particle
collisions. These inter-particle collisions have been shown to be
sufficiently energetic to melt together metal particles at transient
temperatures determined to be up to about 3000° C. at the point of
collision. The inter-particle collisions can also have a dramatic effect
on particle morphology remarkably changing the size, surface, and
composition of particles.

[0039]When a cavitation bubble is formed and collapses near a surface,
another phenomenon is observed. Due to the non-homogeneous boundary
conditions, the bubble implodes asymmetrically and generates a very
small, high-velocity (measured at about 400 km/hr) jet of liquid toward
the surface. This energetic jet can cause severe damage to surfaces and
is the effect responsible for the cavitation erosion that is observed
during ultrasonic liquid processing, as well as any high-speed fluid flow
event that results in cavitation (e.g., liquid pumping, ship propellers).

[0040]When a cavitation bubble is formed and collapses away from a
surface, it does so symmetrically (spherically). A surface must be
several times larger than the bubble to generate asymmetrical bubble
collapse. Therefore, fine particle dispersions will not produce the
liquid jetting effect.

[0041]The ultrasonic cavitation effect is influenced by the frequency and
intensity of the mechanical pressure waves generated within the liquid as
well as the properties of the liquid itself. The number of cavitation
sites is known to be directly proportional to the excitation frequency,
however, the average size of the cavitation bubble is inversely
proportional to the frequency. In water at 20 kHz, the cavitation
threshold intensity has been empirically determined to be 0.3 W/cm2.
Liquid properties that influence cavitation include vapor pressure,
temperature, density, viscosity, and surface tension.

[0042]The ultrasonic treatment device described herein has an advantage
over most other known devices in that it can achieve acoustic intensities
several (3 or more) orders of magnitude above the cavitation threshold
level and significantly higher than other commercial systems.

[0043]The terms "liquid" and "formulation" are used interchangeably to
refer to a single component formulation, a formulation comprised of two
or more components in which at least one of the components is a liquid
such as a liquid-liquid formulation, a liquid-gas formulation, or a
liquid-solid formulation.

[0044]The ultrasonic mixing system 121 is illustrated schematically in
FIG. 1 and further described herein with reference to use of the
treatment chamber 151 in the ultrasonic mixing system to mix various
formulations to create metal-modified particles. The metal-modified
particles can subsequently be used to remove odorous compounds from a
medium such as air or water. For example, in one embodiment, a first
formulation comprising aqueous sodium bicarbonate is ultrasonically mixed
with a second formulation comprising silica nano-particles and a copper
(II) salt aqueous formulation to form copper-modified silica
nano-particles for use in removing odorous compounds. It should be
understood by one skilled in the art that while described herein with
respect to a first formulation comprising aqueous sodium bicarbonate and
a second formulation comprising silica nano-particles and a chloride salt
of copper(II) aqueous formulation, the first formulation may comprise any
basic buffer system and the second formulation may comprise silica
nano-particles with a chloride salt of any transition metal.

[0045]Specifically, the first formulation may comprise any basic buffer
system capable of maintaining the pH of the first formulation from about
8 to about 10. For instance, the basic buffer system may include
potassium hydroxide, sodium hydroxide, ammonium hydroxide, sodium
carbonate, and combinations thereof. Without intending to be limited by
theory, it is believed that the purpose of the base in the buffer system
is to deprotonate the silanol groups on the silica surface, which allows
the transition metal to chemically form a bond with the deprotonated
silanol.

[0046]Further, the silica nano-particles included within the second
formulation may possess various forms, shapes, and sizes depending upon
the desired result. For instance, the silica particles may be in the
shape of a sphere, crystal, rod, disk, tube, string, and the like. The
average size of the silica particles is generally less than about 500
microns, in some embodiments less than about 100 microns, in some
embodiments less than about 100 nanometers, in some embodiments from
about 1 to about 50 nanometers, in some embodiments from about 2 to about
50 nanometers, and in some embodiments, from about 4 to about 20
nanometers. As used herein, the average size of a particle refers to its
average length, width, height, and/or diameter.

[0047]The silica particles may have a surface area of from about 50 square
meters per gram (m2/g) to about 1000 m2/g, in some embodiments
from about 100 m2/g to about 600 m2/g, and in some embodiments,
from about 180 m2/g to about 240 m2/g. Surface area may be
determined by the physical gas adsorption (B.E.T.) method of Brunauer,
Emmet, and Teller, Journal of American Chemical Society, Vol. 60, 1938,
p. 309, with nitrogen as the adsorption gas. If desired, the silica
particles may also be relatively nonporous or solid. That is, the silica
particles may have a pore volume that is less than about 0.5 milliliters
per gram (ml/g), in some embodiments less than about 0.4 milliliters per
gram, in some embodiments less than about 0.3 ml/g, and in some
embodiments, from about 0.2 ml/g to about 0.3 ml/g. Without intending to
be limited by theory, it is believed that silica particles having such
small size and high surface area may improve the adsorption capability of
the silica for many odorous compounds. Moreover, it is believed that the
solid nature, i.e., low pore volume, of the silica particles may enhance
the uniformity and stability of the silica, without sacrificing its odor
adsorption characteristics. Commercially available examples of silica
nano-particles, such as described above, include Snowtex®-C,
Snowtex®-O, Snowtex®-PS, and Snowtex®-OXS, which are
available from Nissan Chemical America Corporation of Houston, Tex.
Snowtex-OXS particles, for instance, have a particle size of from 4 to 6
nanometers, and may be ground into a powder having a surface area of
approximately 509 square meters per gram.

[0048]The concentration of silica particles in the second formulation is
from about 0.01% to about 10% (by weight) in water. In one embodiment,
the concentration of silica particles in the second formulation is at
least about 4% (by weight) in water. In another embodiment, the
concentration of silica particles in the second formulation is about 5%
(by weight) in water.

[0049]Although described herein with respect to silica, other materials
may be used in accordance with the present disclosure to form metal
modified particles. For instance, the particles could be selected from
inorganic materials, such as silica, alumina, or zeolite; metals, such as
silver, copper, or gold; organic materials, such as polystyrene, latex,
polyethylene glycol, or a lipid micelle; or a microbe including a lipid
or saccharide-based wall. Further, the present disclosure may be used in
preparing metal-modified flat surfaces comprised of metal, organic films,
inorganic films, sheets, or fibers.

[0050]In addition, the second formulation may comprise silica
nano-particles with a salt of any transition metal. Examples of suitable
transition metals that may be used in the methods of the present
disclosure, include, but are not limited to, scandium, titanium,
vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,
silver, and gold. The second formulation may comprise silica
nano-particles with chloride salts of Cu(II), Fe(II), Mn(II), and Co(II).
Without being limited by theory, it is believed that the transition metal
provides one or more active sites for capturing and/or neutralizing an
odorous compound. Further, the presence of the transition metal is also
believed to help improve the Lewis acidity of the silica, thus rendering
it more receptive to free electron pairs of many odorous compounds. In
addition, the point of contact for chemical absorption of the odor
compound to the metal-modified silica particle is the metal site. In an
alternative embodiment, other materials may also be used in the second
formulation in accordance with the present disclosure. These other
materials may include metals; organic molecules, such as dyes,
pharmaceuticals, antimicrobials, UV absorbing molecules, and the like;
enzymes, biomolecules; and microbes, such as bacteria, molds, viruses,
and spores. These embedded species may be used for ease of handling, use,
and removal, and could also be used as triggerable controlled release
systems which could release these embedded species when needed.

[0051]The transition metal is present in the second formulation from about
13% to about 40% by weight of the second formulation. The ratio of the
transition metal to the silica particles present in the second
formulation may be selectively varied to achieve the desired results. In
most embodiments, for example, the ratio of the transition metal to the
silica particles is at least about 5:1, in some embodiments at least
about 50:1, and in some embodiments, at least about 200:1. In a preferred
embodiment, the second formulation comprises silica particles dispersed
in a chloride salt of copper(II) aqueous formulation in a ratio of about
50:1.

[0052]In one particularly preferred embodiment, as illustrated in FIG. 1,
the treatment chamber 151 is generally elongate and has a general inlet
end 125 (an upper end in the orientation of the illustrated embodiment)
and a general outlet end 127 (a lower end in the orientation of the
illustrated embodiment). The treatment chamber 151 is configured such
that the first formulation enters the treatment chamber 151 generally at
the inlet end 125 thereof, flows generally longitudinally within the
chamber (e.g., downward in the orientation of illustrated embodiment) and
exits the chamber generally at the outlet end 127 of the chamber.

[0053]The terms "upper" and "lower" are used herein in accordance with the
vertical orientation of the treatment chamber 151 illustrated in the
various drawings and are not intended to describe a necessary orientation
of the chamber in use. That is, while the chamber 151 is most suitably
oriented vertically, with the outlet end 127 of the chamber below the
inlet end 125 as illustrated in the drawing, it should be understood that
the chamber may be oriented with the inlet end below the outlet end and
the first and second formulations are mixed as the first formulation
travels upward through the chamber, or it may be oriented other than in a
vertical orientation and remain within the scope of this disclosure.

[0054]The terms "axial" and "longitudinal" refer directionally herein to
the vertical direction of the chamber 151 (e.g., end-to-end such as the
vertical direction in the illustrated embodiment of FIG. 1). The terms
"transverse", "lateral" and "radial" refer herein to a direction normal
to the axial (e.g., longitudinal) direction. The terms "inner" and
"outer" are also used in reference to a direction transverse to the axial
direction of the treatment chamber 151, with the term "inner" referring
to a direction toward the interior of the chamber and the term "outer"
referring to a direction toward the exterior of the chamber.

[0055]The inlet end 125 of the treatment chamber 151 is in fluid
communication with a suitable delivery system, generally indicated at
129, that is operable to direct one formulation to, and more suitably
through, the chamber 151. Typically, the delivery system 129 may comprise
one or more pumps 171 operable to pump the respective formulation from a
corresponding source thereof to the inlet end 125 of the chamber 151 via
suitable conduits 134.

[0056]It is understood that the delivery system 129 may be configured to
deliver more than one formulation to the treatment chamber 151 without
departing from the scope of this disclosure. It is also contemplated that
delivery systems other than that illustrated in FIG. 1 and described
herein may be used to deliver one or more formulations to the inlet end
125 of the treatment chamber 151 without departing from the scope of this
disclosure. It should be understood that more than one formulation can
refer to two streams of the same formulation or different formulations
being delivered to the inlet end of the treatment chamber without
departing from the scope of the present disclosure.

[0057]The treatment chamber 151 comprises a housing defining an interior
space 153 of the chamber 151 through which the first formulation
delivered to the chamber 151 flows from the inlet end 125 to the outlet
end 127 thereof after the second formulation has been added to the
chamber 151. The chamber housing 151 suitably comprises an elongate tube
155 generally defining, at least in part, a sidewall 157 of the chamber
151. It should be understood by one skilled in the art that the inlet end
of the housing may include one or more inlet ports, two or more inlet
ports, and even three or more inlet ports. For example, FIG. 3, as
discussed in more detail below, illustrates an embodiment comprising an
inlet port for delivering the first formulation to the chamber and a
separate inlet port for delivering the second formulation to the chamber.
Alternatively, although not shown, the housing may comprise three inlet
ports, wherein the first inlet port and the second inlet port are
suitable in parallel, spaced relationship with each other, and the third
inlet port is oriented on the opposite sidewall of the housing from the
first and second inlet ports. Further, it should be understood by one
skilled in the art that an open longitudinal end of the elongate tube 155
may be used as an inlet or an outlet port.

[0058]As shown in FIG. 1, the inlet end 125 is generally open to the
surrounding environment. In an alternative embodiment (not shown),
however, the housing may comprise a closure connected to and
substantially closing the longitudinally opposite end of the sidewall,
and having at least one inlet port therein to generally define the inlet
end of the treatment chamber. The sidewall (e.g., defined by the elongate
tube) of the chamber has an inner surface that together with the
waveguide assembly (as described below) and the closure define the
interior space of the chamber.

[0059]In the illustrated embodiment of FIG. 1, the tube 155 is generally
cylindrical so that the chamber sidewall 157 is generally annular in
cross-section. However, it is contemplated that the cross-section of the
chamber sidewall 157 may be other than annular, such as polygonal or
another suitable shape, and remains within the scope of this disclosure.
The chamber sidewall 157 of the illustrated chamber 151 is suitably
constructed of a transparent material, although it is understood that any
suitable material may be used as long as the material is compatible with
the formulations and particulates being mixed within the chamber, the
pressure at which the chamber is intended to operate, and other
environmental conditions within the chamber such as temperature.

[0060]A waveguide assembly, generally indicated at 203, extends
longitudinally at least in part within the interior space 153 of the
chamber 151 to ultrasonically energize the formulation (and any of its
components) flowing through the interior space 153 of the chamber 151. In
particular, the waveguide assembly 203 of the illustrated embodiment
extends longitudinally from the lower or outlet end 127 of the chamber
151 up into the interior space 153 thereof to a terminal end 113 of the
waveguide assembly disposed intermediate the inlet end 125. Although
illustrated in FIG. 1 as extending longitudinally into the interior space
153 of the chamber 151, it should be understood by one skilled in the art
that the waveguide assembly may extend laterally from a housing sidewall
of the chamber, running horizontally through the interior space thereof
without departing from the scope of the present disclosure. Typically,
the waveguide assembly 203 is mounted, either directly or indirectly, to
the chamber housing 151 as will be described later herein.

[0061]Still referring to FIG. 1, the waveguide assembly 203 suitably
comprises an elongate horn assembly, generally indicated at 133, disposed
entirely with the interior space 153 of the housing 151 intermediate the
inlet end 125 and the outlet port 165 for complete submersion within the
liquid being treated within the chamber 151, and more suitably, in the
illustrated embodiment, it is aligned coaxially with the chamber sidewall
157. The horn assembly 133 has an outer surface 107 that together with an
inner surface 167 of the sidewall 157 defines a flow path within the
interior space 153 of the chamber 151 along which the formulation (and
its components) flow past the horn within the chamber (this portion of
the flow path being broadly referred to herein as the ultrasonic
treatment zone). The horn assembly 133 has an upper end defining a
terminal end of the horn assembly (and therefore the terminal end 113 of
the waveguide assembly) and a longitudinally opposite lower end 111.
Although not shown, it is particularly preferable that the waveguide
assembly 203 also comprises a booster coaxially aligned with and
connected at an upper end thereof to the lower end 111 of the horn
assembly 133. It is understood, however, that the waveguide assembly 203
may comprise only the horn assembly 133 and remain within the scope of
this disclosure. It is also contemplated that the booster may be disposed
entirely exterior of the chamber housing 151, with the horn assembly 133
mounted on the chamber housing 151 without departing from the scope of
this disclosure.

[0062]The waveguide assembly 203, and more particularly the booster is
suitably mounted on the chamber housing 151, e.g., on the tube 155
defining the chamber sidewall 157, at the upper end thereof by a mounting
member (not shown) that is configured to vibrationally isolate the
waveguide assembly (which vibrates ultrasonically during operation
thereof) from the treatment chamber housing. That is, the mounting member
inhibits the transfer of longitudinal and transverse mechanical vibration
of the waveguide assembly 203 to the chamber housing 151 while
maintaining the desired transverse position of the waveguide assembly
(and in particular the horn assembly 133) within the interior space 153
of the chamber housing and allowing both longitudinal and transverse
displacement of the horn assembly within the chamber housing. The
mounting member also at least in part (e.g., along with the booster,
lower end of the horn assembly) closes the outlet end 127 of the chamber
151. Examples of suitable mounting member configurations are illustrated
and described in U.S. Pat. No. 6,676,003, the entire disclosure of which
is incorporated herein by reference to the extent it is consistent
herewith.

[0063]In one particularly suitable embodiment, the mounting member is of
single piece construction. Even more suitably the mounting member may be
formed integrally with the booster (and more broadly with the waveguide
assembly 203). However, it is understood that the mounting member may be
constructed separately from the waveguide assembly 203 and remain within
the scope of this disclosure. It is also understood that one or more
components of the mounting member may be separately constructed and
suitably connected or otherwise assembled together.

[0064]In one suitable embodiment, the mounting member is further
constructed to be generally rigid (e.g., resistant to static displacement
under load) so as to hold the waveguide assembly 203 in proper alignment
within the interior space 153 of the chamber 151. For example, the rigid
mounting member in one embodiment may be constructed of a non-elastomeric
material, more suitably metal, and even more suitably the same metal from
which the booster (and more broadly the waveguide assembly 203) is
constructed. The term "rigid" is not, however, intended to mean that the
mounting member is incapable of dynamic flexing and/or bending in
response to ultrasonic vibration of the waveguide assembly 203. In other
embodiments, the rigid mounting member may be constructed of an
elastomeric material that is sufficiently resistant to static
displacement under load but is otherwise capable of dynamic flexing
and/or bending in response to ultrasonic vibration of the waveguide
assembly 203.

[0065]A suitable ultrasonic drive system 131 including at least an exciter
(not shown) and a power source (not shown) is disposed exterior of the
chamber 151 and operatively connected to the booster (not shown) (and
more broadly to the waveguide assembly 203) to energize the waveguide
assembly to mechanically vibrate ultrasonically. Examples of suitable
ultrasonic drive systems 131 include a Model 20A3000 system available
from Dukane Ultrasonics of St. Charles, Ill., and a Model 2000CS system
available from Herrmann Ultrasonics of Schaumberg, Ill.

[0066]In one embodiment, the drive system 131 is capable of operating the
waveguide assembly 203 at a frequency in the range of about 15 kHz to
about 100 kHz, more suitably in the range of about 15 kHz to about 60
kHz, and even more suitably in the range of about 20 kHz to about 40 kHz.
Such ultrasonic drive systems 131 are well known to those skilled in the
art and need not be further described herein.

[0067]In some embodiments, however not illustrated, the treatment chamber
can include more than one waveguide assembly having at least two horn
assemblies for ultrasonically treating and mixing the phases together to
prepare the emulsion. As noted above, the treatment chamber comprises a
housing defining an interior space of the chamber through which the
formulations are delivered from an inlet end. The housing comprises an
elongate tube defining, at least in part, a sidewall of the chamber. As
with the embodiment including only one waveguide assembly as described
above, the tube may have one or more inlet ports formed therein, through
which at least two formulations to be mixed within the chamber are
delivered to the interior space thereof, and at least one outlet port
through which the particulate-containing formulation exits the chamber.

[0068]In such an embodiment, two or more waveguide assemblies extend
longitudinally at least in part within the interior space of the chamber
to ultrasonically energize and mix the formulations (and resulting
particulate containing formulation) flowing through the interior space of
the chamber. Each waveguide assembly separately includes an elongate horn
assembly, each disposed entirely within the interior space of the housing
intermediate the inlet end 125 and the outlet port for complete
submersion within the formulations being mixed within the chamber. Each
horn assembly can be independently constructed as described more fully
herein (including the horns, along with the plurality of agitating
members and baffle assemblies).

[0069]Referring back to FIG. 1, the horn assembly 133 comprises an
elongate, generally cylindrical horn 105 having an outer surface 107, and
two or more (i.e., a plurality of) agitating members 137 connected to the
horn and extending at least in part transversely outward from the outer
surface of the horn in longitudinally spaced relationship with each
other. The horn 105 is suitably sized to have a length equal to about
one-half of the resonating wavelength (otherwise commonly referred to as
one-half wavelength) of the horn. In one particular embodiment, the horn
105 is suitably configured to resonate in the ultrasonic frequency ranges
recited previously, and most suitably at 20 kHz. For example, the horn
105 may be suitably constructed of a titanium alloy (e.g.,
Ti6Al4V) and sized to resonate at 20 kHz. The one-half
wavelength horn 105 operating at such frequencies thus has a length
(corresponding to a one-half wavelength) in the range of about 4 inches
to about 6 inches, more suitably in the range of about 4.5 inches to
about 5.5 inches, even more suitably in the range of about 5.0 inches to
about 5.5 inches, and most suitably a length of about 5.25 inches (133.4
mm). It is understood, however, that the treatment chamber 151 may
include a horn 105 sized to have any increment of one-half wavelength
without departing from the scope of this disclosure.

[0070]In one embodiment (not shown), the agitating members 137 comprise a
series of five washer-shaped rings that extend continuously about the
circumference of the horn in longitudinally spaced relationship with each
other and transversely outward from the outer surface of the horn. In
this manner the vibrational displacement of each of the agitating members
relative to the horn is relatively uniform about the circumference of the
horn. It is understood, however, that the agitating members need not each
be continuous about the circumference of the horn. For example, the
agitating members may instead be in the form of spokes, blades, fins or
other discrete structural members that extend transversely outward from
the outer surface of the horn. For example, as illustrated in FIG. 1, one
of the five agitating members is in a T-shape 701. Specifically, the
T-shaped agitating member 701 surrounds the nodal region. It has been
found that members in the T-shape, generate a strong radial (e.g.,
horizontal) acoustic wave that further increases the cavitation effect as
described more fully herein.

[0071]By way of a dimensional example, the horn assembly 133 of the
illustrated embodiment of FIG. 1 has a length of about 5.25 inches (133.4
mm), one of the rings 137 is suitably disposed adjacent the terminal end
113 of the horn 105 (and hence of the waveguide assembly 203), and more
suitably is longitudinally spaced approximately 0.063 inches (1.6 mm)
from the terminal end of the horn 105. In other embodiments the uppermost
ring may be disposed at the terminal end of the horn 105 and remain
within the scope of this disclosure. The rings 137 are each about 0.125
inches (3.2 mm) in thickness and are longitudinally spaced from each
other (between facing surfaces of the rings) a distance of about 0.875
inches (22.2 mm).

[0072]It is understood that the number of agitating members 137 (e.g., the
rings in the illustrated embodiment) may be less than or more than five
without departing from the scope of this disclosure. It is also
understood that the longitudinal spacing between the agitating members
137 may be other than as illustrated in FIG. 1 and described above (e.g.,
either closer or spaced further apart). Furthermore, while the rings 137
illustrated in FIG. 1 are equally longitudinally spaced from each other,
it is alternatively contemplated that where more than two agitating
members are present the spacing between longitudinally consecutive
agitating members need not be uniform to remain within the scope of this
disclosure.

[0073]In particular, the locations of the agitating members 137 are at
least in part a function of the intended vibratory displacement of the
agitating members upon vibration of the horn assembly 133. For example,
in the illustrated embodiment of FIG. 1, the horn assembly 133 has a
nodal region located generally longitudinally centrally of the horn 105
(e.g., at the third ring). As used herein and more particularly shown in
FIG. 1, the "nodal region" of the horn 105 refers to a longitudinal
region or segment of the horn member along which little (or no)
longitudinal displacement occurs during ultrasonic vibration of the horn
and transverse (e.g., radial in the illustrated embodiment) displacement
of the horn is generally maximized. Transverse displacement of the horn
assembly 133 suitably comprises transverse expansion of the horn but may
also include transverse movement (e.g., bending) of the horn.

[0074]In the illustrated embodiment of FIG. 1, the configuration of the
one-half wavelength horn 105 is such that the nodal region is
particularly defined by a nodal plane (i.e., a plane transverse to the
horn member at which no longitudinal displacement occurs while transverse
displacement is generally maximized) is present. This plane is also
sometimes referred to as a "nodal point". Accordingly, agitating members
137 (e.g., in the illustrated embodiment, the rings) that are disposed
longitudinally further from the nodal region of the horn 105 will
experience primarily longitudinal displacement while agitating members
that are longitudinally nearer to the nodal region will experience an
increased amount of transverse displacement and a decreased amount of
longitudinal displacement relative to the longitudinally distal agitating
members.

[0075]It is understood that the horn 105 may be configured so that the
nodal region is other than centrally located longitudinally on the horn
member without departing from the scope of this disclosure. It is also
understood that one or more of the agitating members 137 may be
longitudinally located on the horn so as to experience both longitudinal
and transverse displacement relative to the horn upon ultrasonic
vibration of the horn 105.

[0076]Still referring to FIG. 1, the agitating members 137 are
sufficiently constructed (e.g., in material and/or dimension such as
thickness and transverse length, which is the distance that the agitating
member extends transversely outward from the outer surface 107 of the
horn 105) to facilitate dynamic motion, and in particular dynamic
flexing/bending of the agitating members in response to the ultrasonic
vibration of the horn. In one particularly suitable embodiment, for a
given ultrasonic frequency at which the waveguide assembly 203 is to be
operated in the treatment chamber (otherwise referred to herein as the
predetermined frequency of the waveguide assembly) and a particular
liquid to be treated within the chamber 151, the agitating members 137
and horn 105 are suitably constructed and arranged to operate the
agitating members in what is referred to herein as an ultrasonic
cavitation mode at the predetermined frequency.

[0077]As used herein, the ultrasonic cavitation mode of the agitating
members refers to the vibrational displacement of the agitating members
sufficient to result in cavitation (i.e., the formation, growth, and
implosive collapse of bubbles in a liquid) of the formulation being
prepared at the predetermined ultrasonic frequency. For example, where
the formulations (and particulates) flowing within the chamber comprise
aqueous liquid formulations, and the ultrasonic frequency at which the
waveguide assembly 203 is to be operated (i.e., the predetermined
frequency) is about 20 kHZ, one or more of the agitating members 137 are
suitably constructed to provide a vibrational displacement of at least
1.75 mils (i.e., 0.00175 inches, or 0.044 mm) to establish a cavitation
mode of the agitating members.

[0078]It is understood that the waveguide assembly 203 may be configured
differently (e.g., in material, size, etc.) to achieve a desired
cavitation mode associated with the particular formulation and/or
particulates to be mixed. For example, as the viscosity of the
formulation being mixed with the particulates changes, the cavitation
mode of the agitating members may need to be changed.

[0079]In particularly suitable embodiments, the cavitation mode of the
agitating members corresponds to a resonant mode of the agitating members
whereby vibrational displacement of the agitating members is amplified
relative to the displacement of the horn. However, it is understood that
cavitation may occur without the agitating members operating in their
resonant mode, or even at a vibrational displacement that is greater than
the displacement of the horn, without departing from the scope of this
disclosure.

[0080]In one suitable embodiment, a ratio of the transverse length of at
least one and, more suitably, all of the agitating members to the
thickness of the agitating member is in the range of about 2:1 to about
6:1. As another example, the rings each extend transversely outward from
the outer surface 107 of the horn 105 a length of about 0.5 inches (12.7
mm) and the thickness of each ring is about 0.125 inches (3.2 mm), so
that the ratio of transverse length to thickness of each ring is about
4:1. It is understood, however that the thickness and/or the transverse
length of the agitating members may be other than that of the rings as
described above without departing from the scope of this disclosure.
Also, while the agitating members 137 (rings) may suitably each have the
same transverse length and thickness, it is understood that the agitating
members may have different thicknesses and/or transverse lengths.

[0081]In the above described embodiment, the transverse length of the
agitating member also at least in part defines the size (and at least in
part the direction) of the flow path along which the formulations and
particulates or other flowable components in the interior space of the
chamber flows past the horn. For example, the horn may have a radius of
about 0.875 inches (22.2 mm) and the transverse length of each ring is,
as discussed above, about 0.5 inches (12.7 mm). The radius of the inner
surface of the housing sidewall is approximately 1.75 inches (44.5 mm) so
that the transverse spacing between each ring and the inner surface of
the housing sidewall is about 0.375 inches (9.5 mm). It is contemplated
that the spacing between the horn outer surface and the inner surface of
the chamber sidewall and/or between the agitating members and the inner
surface of the chamber sidewall may be greater or less than described
above without departing from the scope of this disclosure.

[0082]In general, the horn 105 may be constructed of a metal having
suitable acoustical and mechanical properties. Examples of suitable
metals for construction of the horn 105 include, without limitation,
aluminum, monel, titanium, stainless steel, and some alloy steels. It is
also contemplated that all or part of the horn 105 may be coated with
another metal such as silver, platinum, gold, palladium, lead dioxide,
and copper to mention a few. In one particularly suitable embodiment, the
agitating members 137 are constructed of the same material as the horn
105, and are more suitably formed integrally with the horn. In other
embodiments, one or more of the agitating members 137 may instead be
formed separate from the horn 105 and connected thereto.

[0083]While the agitating members 137 (e.g., the rings) illustrated in
FIG. 1 are relatively flat, i.e., relatively rectangular in
cross-section, it is understood that the rings may have a cross-section
that is other than rectangular without departing from the scope of this
disclosure. The term "cross-section" is used in this instance to refer to
a cross-section taken along one transverse direction (e.g., radially in
the illustrated embodiment) relative to the horn outer surface 107).
Additionally, as seen of the first two and last two agitating members 137
(e.g., the rings) illustrated in FIG. 1 are constructed only to have a
transverse component, it is contemplated that one or more of the
agitating members may have at least one longitudinal (e.g., axial)
component to take advantage of transverse vibrational displacement of the
horn (e.g., at the third agitating member as illustrated in FIG. 1)
during ultrasonic vibration of the waveguide assembly 203.

[0084]As best illustrated in FIG. 1, the terminal end 113 of the waveguide
assembly (e.g., of the horn 105 in the illustrated embodiment) is
suitably spaced longitudinally from the inlet end 125 in FIG. 1 to define
what is referred to herein as a liquid intake zone in which initial
swirling of liquid within the interior space 153 of the chamber housing
151 occurs upstream of the horn 105. This intake zone is particularly
useful where the treatment chamber 151 is used for mixing two or more
components together (such as with the particulates and the formulation or
with two or more components of the formulation from inlet end 125 in FIG.
1) whereby initial mixing is facilitated by the swirling action in the
intake zone as the components to be mixed enter the chamber housing 151.
It is understood, though, that the terminal end of the horn 105 may be
nearer to the inlet end 125 than is illustrated in FIG. 1, and may be
substantially adjacent to the inlet end 125 so as to generally omit the
intake zone, without departing from the scope of this disclosure.

[0085]Additionally, a baffle assembly, generally indicated at 245 is
disposed within the interior space 153 of the chamber housing 151, and in
particular generally transversely adjacent the inner surface 167 of the
sidewall 157 and in generally transversely opposed relationship with the
horn 105. In one suitable embodiment, the baffle assembly 245 comprises
one or more baffle members 247 disposed adjacent the inner surface 167 of
the housing sidewall 157 and extending at least in part transversely
inward from the inner surface of the sidewall 167 toward the horn 105.
More suitably, the one or more baffle members 247 extend transversely
inward from the housing sidewall inner surface 167 to a position
longitudinally intersticed with the agitating members 137 that extend
outward from the outer surface 107 of the horn 105. The term
"longitudinally intersticed" is used herein to mean that a longitudinal
line drawn parallel to the longitudinal axis of the horn 105 passes
through both the agitating members 137 and the baffle members 247. As one
example, in the illustrated embodiment, the baffle assembly 245 comprises
four, generally annular baffle members 247 (i.e., extending continuously
about the horn 105) longitudinally intersticed with the five agitating
members 137.

[0086]As a more particular example, the four annular baffle members 247
illustrated in FIG. 1 are of the same thickness as the agitating members
137 in our previous dimensional example (i.e., 0.125 inches (3.2 mm)) and
are spaced longitudinally from each other (e.g., between opposed faces of
consecutive baffle members) equal to the longitudinal spacing between the
rings (i.e., 0.875 inches (22.2 mm)). Each of the annular baffle members
247 has a transverse length (e.g., inward of the inner surface 167 of the
housing sidewall 157) of about 0.5 inches (12.7 mm) so that the innermost
edges of the baffle members extend transversely inward beyond the
outermost edges of the agitating members 137 (e.g., the rings). It is
understood, however, that the baffle members 247 need not extend
transversely inward beyond the outermost edges of the agitating members
137 of the horn 105 to remain within the scope of this disclosure.

[0087]It will be appreciated that the baffle members 247 thus extend into
the flow path of the formulations and particulates that flow within the
interior space 153 of the chamber 151 past the horn 105 (e.g., within the
ultrasonic treatment zone). As such, the baffle members 247 inhibit the
formulations and particulates from flowing along the inner surface 167 of
the chamber sidewall 157 past the horn 105, and more suitably the baffle
members facilitate the flow of the formulations and particulates
transversely inward toward the horn for flowing over the agitating
members of the horn to thereby facilitate ultrasonic energization (i.e.,
agitation) of the formulations and particulates to initiate mixing of the
formulations and particulates within the carrier liquid to form the
metal-modified particles. The baffle members further facilitate the
prevention of agglomeration of the particles within the formulations.

[0088]In one embodiment, to inhibit gas bubbles against stagnating or
otherwise building up along the inner surface 167 of the sidewall 157 and
across the face on the underside of each baffle member 247, e.g., as a
result of agitation of the phases within the chamber, a series of notches
(broadly openings) may be formed in the outer edge of each of the baffle
members (not shown) to facilitate the flow of gas (e.g., gas bubbles)
between the outer edges of the baffle members and the inner surface of
the chamber sidewall. For example, in one particularly preferred
embodiment, four such notches are formed in the outer edge of each of the
baffle members in equally spaced relationship with each other. It is
understood that openings may be formed in the baffle members other than
at the outer edges where the baffle members abut the housing, and remain
within the scope of this disclosure. It is also understood, that these
notches may number more or less than four, as discussed above, and may
even be completely omitted.

[0089]It is further contemplated that the baffle members 247 need not be
annular or otherwise extend continuously about the horn 105. For example,
the baffle members 247 may extend discontinuously about the horn 105,
such as in the form of spokes, bumps, segments or other discrete
structural formations that extend transversely inward from adjacent the
inner surface 167 of the housing sidewall 157. The term "continuously" in
reference to the baffle members 247 extending continuously about the horn
does not exclude a baffle member as being two or more arcuate segments
arranged in end-to-end abutting relationship, i.e., as long as no
significant gap is formed between such segments. Suitable baffle member
configurations are disclosed in U.S. application Ser. No. 11/530,311
(filed Sep. 8, 2006), which is hereby incorporated by reference to the
extent it is consistent herewith.

[0090]Also, while the baffle members 247 illustrated in FIG. 1 are each
generally flat, e.g., having a generally thin rectangular cross-section,
it is contemplated that one or more of the baffle members may each be
other than generally flat or rectangular in cross-section to further
facilitate the flow of bubbles along the interior space 153 of the
chamber 151. The term "cross-section" is used in this instance to refer
to a cross-section taken along one transverse direction (e.g., radially
in the illustrated embodiment, relative to the horn outer surface 107).

[0091]In one embodiment, as illustrated in FIG. 2, the treatment chamber
may further be in connection with a liquid recycle loop, generally
indicated at 400. Typically, the liquid recycle loop 400 is disposed
longitudinally between the inlet end 225 and the outlet port 265. The
liquid recycle loop 400 recycles a portion of the first and second
formulations being mixed within the interior space 253 of the housing 251
back into the intake zone (generally indicated at 261) of the interior
space 253 of the housing 251. By recycling the first and second
formulations back into the intake zone, more effective mixing between the
formulations (and its components) and particulates can be achieved as the
formulations and particulates are allowed to remain within the treatment
chamber, undergoing cavitation, for a longer residence time. Furthermore,
the agitation in the upper portion of the chamber (i.e., intake zone) can
be enhanced, thereby facilitating better dispersing and/or dissolution of
the particulates into the formulations.

[0092]The liquid recycle loop can be any system that is capable of
recycling the liquid formulation from the interior space of the housing
downstream of the intake zone back into the intake zone of the interior
space of the housing. In one particularly preferred embodiment, as shown
in FIG. 2, the liquid recycle loop 400 includes one or more pumps 402 to
deliver the formulation back into the intake zone 261 of the interior
space 253 of the housing 251. The liquid recycle loop 400 further
includes a heat exchanger 404 to cool the formulation passing through the
liquid recycle loop 400 prior to re-entering the intake zone 261 of the
interior space 253 of the housing 251.

[0093]Typically, the first and second formulations (and particulates) are
delivered back into the treatment chamber at a flow rate having a ratio
of recycle flow rate to initial feed flow rate of the formulations
(described below) of 1.0 or greater. While a ratio of recycle flow rate
to initial feed flow rate is preferably greater than 1.0, it should be
understood that ratios of less than 1.0 can be tolerated without
departing from the scope of the present disclosure.

[0094]Although the energy created by the ultrasonic horn 233 substantially
reduces agglomeration within the treatment chamber, many particulates,
when initially added to a formulation, may still attract one another and
clump together in large balls. Furthermore, many times, particles in the
particulate-containing formulations can settle out over time and attract
one another to form large balls; referred to as reagglomeration. As such,
in one embodiment, the ultrasonic mixing system may further comprise a
filter assembly disposed at the outlet end of the treatment chamber. The
filter assembly can filter out the large balls of particulates that form
within the particulate-containing formulation prior to the formulation
being delivered to a packaging unit for consumer use, as described more
fully below. Specifically, the filter assembly is constructed to filter
out particulates sized greater than about 0.2 microns.

[0095]Specifically, in one particularly preferred embodiment, the filter
assembly covers the inner surface of the outlet port. The filter assembly
includes a filter having a pore size of from about 0.5 micron to about 20
microns. More suitably, the filter assembly includes a filter having a
pore size of from about 1 micron to about 5 microns, and even more
suitably, about 2 microns. The number and pour size of filters for use in
the filter assembly will typically depend on the particulates and
formulation to be mixed within the treatment chamber.

[0096]A degasser may also be included in the ultrasonic mixing system. For
example, once the prepared particulate-containing formulation exits the
treatment chamber, the particulate-containing formulation flows into a
degasser in which excess gas bubbles are removed from the
particulate-containing formulation prior to the particulate-containing
formulation being used into a consumer end-products.

[0097]One particularly preferred degasser is a continuous flow gas-liquid
cyclone separator, such as commercially available from NATCO (Houston,
Tex.). It should be understood by a skilled artisan, however, that any
other system that separates gas from an emulsion by centrifugal action
can suitably be used without departing from the present disclosure.

[0098]In a third embodiment, the treatment chamber 351 has a general inlet
end 325 (a lower end in the orientation of the illustrated embodiment)
and a general outlet end 327 (an upper end in the orientation of the
illustrated embodiment). The treatment chamber 351 is configured such
that the first and second formulations enter the treatment chamber 351
generally at the inlet end 325 thereof, flow generally longitudinally
within the chamber (e.g., upward in the orientation of illustrated
embodiment) and exit the chamber generally at the outlet end 327 of the
chamber. It should be recognized by one skilled in the art that the
chamber of this particular embodiment may be oriented other than in a
vertical orientation and remain within the scope of this disclosure.

[0099]The inlet end 325 of the treatment chamber 351 is typically in fluid
communication with at least one suitable delivery system that is operable
to direct a formulation to, and more suitably through, the chamber 151.
More specifically, as illustrated in FIG. 3, two delivery systems 328 and
329 are operable to direct a first formulation (not shown) and a second
formulation (not shown) through the chamber 351. Typically, the delivery
systems 328, 329 may independently comprise one or more pumps 370 and
371, respectively, operable to pump the respective phases from
corresponding sources thereof to the inlet end 325 of the chamber 351 via
suitable conduits 332, 334.

[0100]The treatment chamber 351 comprises a housing defining an interior
space 353 of the chamber 351 through which at least two formulations
delivered to the chamber 351 flow from the inlet end 325 to the outlet
end 327 thereof. The chamber housing 351 suitably comprises an elongate
tube 355 generally defining, at least in part, a sidewall 357 of the
chamber 351. The tube 355 may have one or more inlet ports (two inlet
ports are generally indicated in FIG. 3 at 356 and 358) formed therein
through which at least two separate formulations to be mixed within the
chamber 351 are delivered to the interior space 353 thereof. It should be
understood by one skilled in the art that the inlet end of the housing
may include more than two inlet ports, more than three ports, and even
more than four ports. By way of example, although not shown, the housing
may comprise three inlet ports, wherein the first inlet port and the
second inlet port are suitably in parallel, spaced relationship with each
other, and the third inlet port is oriented on the opposite sidewall of
the housing from the first and second inlet ports.

[0101]It should also be recognized by one skilled in the art that, while
preferably the inlet ports are disposed in close proximity to one another
in the inlet end, the inlet ports may be spaced farther along the
sidewall of the chamber from one another without departing from the scope
of the present disclosure.

[0102]As illustrated in FIG. 3, the treatment chamber may further be in
connection with a liquid recycle loop, generally indicated at 500.
Typically, the liquid recycle loop 500 is disposed longitudinally between
the inlet end 325 and the outlet end 327. The liquid recycle loop 500
recycles a portion of the first and second formulations being mixed
within the interior space 353 of the housing 351 back into an intake zone
(generally indicated at 361) of the interior space 353 of the housing
351. By recycling the first and second formulations back into the intake
zone, more effective mixing between the formulations (and its components)
and particulates can be achieved as the formulations and particulates are
allowed to remain within the treatment chamber, undergoing cavitation,
for a longer residence time. Furthermore, the agitation in the upper
portion of the chamber (i.e., intake zone) can be enhanced, thereby
facilitating better dispersing and/or dissolution of the particulates
into the formulations.

[0103]The liquid recycle loop can be any system that is capable of
recycling the liquid formulation from the interior space of the housing
downstream of the intake zone back into the intake zone of the interior
space of the housing. In one particularly preferred embodiment, as shown
in FIG. 3, the liquid recycle loop 500 includes one or more pumps 502 to
deliver the formulation back into the intake zone 361 of the interior
space 353 of the housing 351. The liquid recycle loop 500 further
includes a heat exchanger 504 to cool the formulation passing through the
liquid recycle loop 500 prior to the formulation re-entering the intake
zone 361 of the interior space 353 of the housing 351.

[0104]Typically, the first and second formulations (and particulates) are
delivered back into the treatment chamber at a flow rate having a ratio
of recycle flow rate to initial feed flow rate of the formulations
(described below) of 1.0 or greater. While a ratio of recycle flow rate
to initial feed flow rate is preferably greater than 1.0, it should be
understood that ratios of less than 1.0 can be tolerated without
departing from the scope of the present disclosure.

[0105]In operation according to one embodiment of the ultrasonic mixing
system of the present disclosure, the mixing system (more specifically,
the treatment chamber) is used to mix/disperse particulates into one or
more formulations. Specifically, a first formulation is delivered (e.g.,
by the pumps described above) via conduits to the inlet end (FIGS. 1 and
2) or to one or more inlet ports formed in the treatment chamber housing
(FIG. 3). The first formulation can be any suitable basic buffer system
known in the art. For example, the first formulation may comprise sodium
bicarbonate, potassium hydroxide, sodium hydroxide, ammonium hydroxide,
sodium carbonate, or combinations thereof.

[0106]Generally, from about 0.1 grams per minute to about 100,000 grams
per minute of the first formulation is typically delivered into the
treatment chamber housing. More suitably, the amount of formulation
delivered into the treatment chamber housing is from about 1 gram per
minute to about 10,000 grams per minute. In the preferred embodiment, the
first formulation comprises aqueous sodium bicarbonate with a
concentration of from about 0.01 M to about 0.6 M. More preferably, the
first formulation comprises aqueous sodium bicarbonate having a
concentration of 0.4 M.

[0107]With the ultrasonic horn turned on, the first formulation is pumped
through a conduit to the inlet end (FIGS. 1 and 2) or to an inlet port
disposed on the treatment chamber housing (FIG. 3). In one embodiment, as
shown in FIGS. 1 and 2, the first formulation is pumped through the inlet
end of the treatment chamber housing. The conduit through which the first
formulation is delivered may be moved up and down during delivery to
assure composition uniformity in the treatment chamber. In another
embodiment, as shown in FIG. 3, the first formulation is continuously
pumped through a conduit to an inlet port disposed at the inlet end 325
(a lower end in the orientation of the illustrated embodiment in FIG. 3)
at a flow rate to maintain the required concentration of the first
formulation within the treatment chamber.

[0108]Additionally, the method includes delivering a second formulation,
such as those described above, to the interior space of the chamber. In
one embodiment, as shown in FIGS. 1 and 2, the second formulation is
placed into the interior of the chamber prior to the first formulation
being delivered to the chamber. In another embodiment, the second
formulation is continuously pumped through a conduit to an inlet port 358
disposed at the inlet end 325 (a lower end in the orientation of the
illustrated embodiment in FIG. 3) at a flow rate to maintain the required
concentration of the first formulation within the treatment chamber. In
this particular embodiment, the second formulation is delivered to the
chamber at a rate of from about 0.0001 L/min to about 100 L/min.
Preferably, the second formulation is delivered at a rate of from about
0.001 L/min to about 0.100 L/min.

[0109]In accordance with the above embodiments, as the formulation and
particulates flow downward (as in FIGS. 1 and 2) or upward (as in FIG. 3)
within the chamber, the waveguide assembly, and more particularly the
horn assembly, is driven by the drive system to vibrate at a
predetermined ultrasonic frequency. In response to ultrasonic excitation
of the horn, the agitating members that extend outward from the outer
surface of the horn dynamically flex/bend relative to the horn, or
displace transversely (depending on the longitudinal position of the
agitating member relative to the nodal region of the horn).

[0110]The formulations and particulates continuously flow longitudinally
along the flow path between the horn assembly and the inner surface of
the housing sidewall so that the ultrasonic vibration and the dynamic
motion of the agitating members cause cavitation in the formulation to
further facilitate agitation. The baffle members disrupt the longitudinal
flow of formulation along the inner surface of the housing sidewall and
repeatedly direct the flow transversely inward to flow over the vibrating
agitating members.

[0111]As the mixed particulate-containing formulation flows longitudinally
past the terminal end of the waveguide assembly, an initial back mixing
of the particulate-containing formulation also occurs as a result of the
dynamic motion of the agitating member at or adjacent the terminal end of
the horn. Further, downstream flow of the particulate-containing
formulation, as in FIGS. 1 and 2, results in the agitated formulation
providing a more uniform mixture of components (e.g., components of
formulation and particulates) prior to exiting the treatment chamber via
the outlet port. Further, by utilizing ultrasonic energy created by the
ultrasonic horn described above, agglomeration of particles within the
treatment chamber is significantly reduced, and thus, a more fine and
homogenous powder may be produced upon isolation. In addition, it has
been found that by utilizing ultrasonic energy during the mixing of the
first and second formulations described above, a metal-modified particle
may be formed that is capable of removing odorous compounds via chemical
absorption.

[0112]In one embodiment, as illustrated in FIG. 2 and FIG. 3, as the
particulate-containing formulation travels through the chamber, a portion
of the first and second formulations are directed out of the housing
prematurely through the liquid recycle loop as described above. This
portion of the first and second formulations is then delivered back into
the intake zone of the interior space of the housing of the treatment
chamber to be mixed with fresh formulation and particulates. By recycling
a portion of the first and second formulations, a more thorough mixing of
the formulations and particulates occurs.

[0113]Once the particulate-containing formulation is thoroughly mixed, the
particulate-containing formulation exits the treatment chamber via the
outlet port. In one embodiment, once exited, the particulate-containing
formulation can be directed to a post-processing delivery system to be
delivered to one or more packaging units where it may be used directly
for spraying onto a material substrate or in a dip and squeeze process.

[0114]In another embodiment, the metal-modified particles may be
recovered, or isolated, from the formulation by filtration and
subsequently washed. For example, a fritted glass filter may be used
where the pore size of the frit is smaller than the particulate size in
diameter, length, or width, and this filter is attached to a filter
flask. The particulate containing formulation is transferred to the
filter, and a vacuum is applied via a connection to the filter flask. The
liquid component of the particulate containing formulation is pulled
through the fritted filter and separated from the particles. The
particulates are washed with water, and the same mechanism is used to
isolate the particulates from the wash liquid.

[0115]In a further embodiment, where isolated metal-modified particles are
desired for dry-condition applications, the aqueous solvent is removed en
vacuo and the isolated particles are washed and dried. For example, a
rotovapor instrument, such as a Buchi Rotavapor R-114 from Buchi
Labortechnik AG (Flawil, Switzerland), may be used to evaporate the
liquid from the particulate containing formulation using applied heat and
vacuum. The remaining particulate is collected and washed with water
using a fritted filter attached to a flask. Further, the
particulate-containing formulation exiting the treatment chamber may be
directly filtered to collect the isolated metal-modified particles and
then washed and air-dried.

[0116]The present disclosure is illustrated by the following examples
which are merely for the purpose of illustration and are not to be
regarded as limiting the scope of the disclosure or manner in which it
may be practiced.

[0117]Quantitative analysis of odor adsorption was determined as described
in the Examples described below using Headspace Gas Chromatography. The
analyses were conducted on an Agilent Technologies 5890, Series II gas
chromatograph with an Agilent Technology 7694 headspace sampler obtained
from Agilent Technologies, Waldbronn, Germany. Helium was used as the
carrier gas with an injection port pressure of 12.7 psig, a headspace
vial pressure of 15.8 psig, and a supply line pressure of 60 psig. A
DB-624 column having a length of 30 meters and an internal diameter of
0.25 millimeters was used for the odorous compound. Such a column is
available from J&W Scientific, Inc. of Folsom, Calif. The operating
parameters used for the headspace gas chromatography are shown below in
Table 1.

[0118]To test a sample, from about 3 mg to about 10 mg of the sample
powder was placed in a 20 cubic centimeter headspace vial. Using a
syringe, an aliquot of the odorous compound, methyl mercaptan, was
transferred to the side wall in the vial. The volume of ethyl mercaptan
ranged from about 839 micrograms (about 1 microliter) to about 3356
micrograms (about 4 microliters). Each test sample was analyzed in
triplicate.

[0119]After transfer of ethyl mercaptan to a test vial, the test vial was
immediately sealed with a cap and a septum and placed in the headspace
gas chromatography oven at 37° C. After a set equilibrium time of
approximately 10 to 23 minutes, a hollow needle was inserted through the
septum and into the vial. A one cubic centimeter sample of the headspace,
or the air inside the vial, was then injected into the gas chromatograph.

[0120]Initially, a control vial with only the aliquot of ethyl mercaptan
was tested to define 0% odorous compound adsorption. To calculate the
amount of headspace odorous compound removed by each sample, the peak
area for the ethyl mercaptan from the vial with the sample was compared
to the peak area from the ethyl mercaptan control vial.

EXAMPLE 1

[0121]In this Example, various types of silica particles were mixed with
copper chloride dihydrate dissolved in aqueous sodium bicarbonate with
and without the presence of ultrasonic energy to form metal-modified
silica particles. The chemical mechanisms by which the metal-modified
silica particles remove odorous compounds were compared.

[0122]Three different samples were prepared using Snowtex®-OXS,
Snowtex®-C, and Snowtex®-PSSO at 5% wt/wt in an aqueous
suspension. Initially, a 100 mL Snowtex®-OXS suspension was added to
the ultrasonic chamber comprising the horn, agitating members, and baffle
system described above in detail. 8.92 grams of copper chloride dihydrate
was dissolved in 700 mL of water, and this solution was added to the
ultrasonic chamber. The ultrasonic mixing system was then ultrasonically
activated using the ultrasonic drive system at 2.4 kW. 6.05 grams of
sodium bicarbonate was slowly added to the top of the ultrasonic mixing
system. The mole ratio of copper (II) chloride dihydrate to the silica
particles was about 50:1, and the final concentration of sodium
bicarbonate in the reaction suspension was about 0.04M.

[0123]This process was repeated for each of Snowtex®-C and
Snowtex®-PSSO. In these two processes, however, the sodium
bicarbonate was added to the ultrasonic mixing system at the bottom of
the chamber. Agglomeration and gelation were not observed for the
processes utilizing Snowtex®-C and Snowtex®-PSSO. Agglomeration
was observed, however, for the process utilizing Snowtex®-OXS.

[0124]Ethyl mercaptan (EtSH) removal assessment was carried out using
headspace GC techniques, described in more detail below (See Example 4).
Specifically, powder samples of CuOXS synthesized with and without
ultrasound energy by the methods described above were isolated via
rotovap and washed with an excessive amount of water. Approximately 10 mg
of powder samples were placed in sample vials, followed by the injection
of 4 microliters of neat EtSH. The sample vials were immediately sealed
and data collection commenced appropriately using established protocols
described above.

[0125]The data directed to the CuOXS preparation without the use of
ultrasound showed increasing removal efficacy over time, which suggests a
catalytic mechanism for removal of EtSH. The data directed to the CuOXS
preparation with the use of ultrasound, however, showed that the removal
of EtSH by the ultrasonically prepared metal-modified silica particles
was stable over time. More specifically, this data suggests that there
was a finite chemical absorption over time, i.e., a saturation point may
have been reached. As such, this data illustrates that chemical
absorption is the odor removal mechanism for metal-modified silica
particles prepared using ultrasonic energy. Chemical absorption is
preferred over catalysis, as chemical absorption involves the chemical
binding of the odor compound to the odor removal compound, and thus, as
opposed to catalysis, is irreversible when subject to physical challenges
such as temperature and humidity. These results are illustrated in FIG.
4.

EXAMPLE 2

[0126]In this Example, metal-modified silica particles were prepared
without the presence of ultrasonic energy. Specifically, a 5% wt/wt
modified silica suspension was prepared by mixing a 10% wt/wt silica
suspension, a copper (II) chloride dihydrate solution, a sodium
bicarbonate solution, and water at the appropriate concentrations and
volumes in a beaker. The mole ratio of copper (II) chloride dihydrate to
silica particles was about 50:1, and the final concentration of sodium
bicarbonate in the reaction suspension was about 0.04 M. the volume of
the reaction suspension was one liter. The silica suspension was obtained
from Nissan Chemical America Corporation of Houston, Tex. under the
tradename Snowtex® OXS, the copper (II) chloride dihydrate solution
was obtained from Aldrich Chemical, and the sodium bicarbonate solution
was obtained from Aldrich Chemical.

[0127]Specifically, the copper (II) chloride dihydrate solution was added
to the silica suspension as the silica suspension was vigorously stirred
using a magnetic stir bar. The sodium bicarbonate solution was then
slowly added at a rate of approximately 5 mL/min to the copper (II)
chloride dihydrate solution and silica suspension. The final formulation
contained 5% wt/wt silica, a 50:1 ratio of copper ions to silica
particles, and 0.04M (aq) sodium bicarbonate.

[0128]Isolation of solid copper modified silica particles was achieved by
removal of water en vacuo, followed by a wash with water and air
filtration. Specifically, a rotovapor instrument was used to evaporate
the liquid from the particulate containing formulation using applied heat
and vacuum. The remaining particulate was controlled and washed with
water using a fritted filter attached to a filter flask.

EXAMPLE 3

[0129]This Example demonstrated the ability to form copper modified silica
nanoparticles using ultrasonic energy. Specifically, the process as
described above in Example 2 was carried out in an ultrasonic chamber of
an ultrasonic mixing system, as is described above in detail. The
ultrasonic mixing system was ultrasonically activated using the
ultrasonic drive system at 2.4 kW prior to the addition of the sodium
bicarbonate solution. When the reaction temperature inside the ultrasonic
mixing system reached a temperature of 180° F., the ultrasonic
drive system was reduced to an output of 1.8 kW and remained constant
through the remainder of the reaction. The particles were then isolated
in the same manner as described in Example 2.

EXAMPLE 4

[0130]This Example demonstrated the effectiveness of copper modified
silica nanoparticles to remediate ethyl mercaptan. The modified silica
particles of Example 2 and Example 3 were tested for ethyl mercaptan
remediation using Headspace Gas Chromatography, as is described in more
detail below. In addition, activated carbon obtained from Meadwestvaco of
Glenn Allen, Va. was tested for comparison. Measurement was recorded
approximately 25 minutes after introduction of ethyl mercaptan into a
sample vial containing either the modified silica particles of Example 2,
the modified silica particles of Example 3, or the activated carbon. The
results are shown below in Table 2.

[0131]As shown in Table 2, the highest amount of ethyl mercaptan per gram
of test sample was removed by the CuOXS particles of Example 2, wherein
no ultrasonic energy was present. This data demonstrates that application
of ultrasonic energy during the preparation of metal-modified silica
particles does not interfere with the ability of the metal-modified
silica particles' ability to remediate ethyl mercaptan.

EXAMPLE 5

[0132]This Example demonstrated the effectiveness of copper modified
silica nanoparticles to remediate ethyl mercaptan over a period of time.
The modified silica particles of Example 2 and Example 3 were tested for
ethyl mercaptan remediation using Headspace Gas Chromatography, as is
described in more detail below. In addition, activated carbon obtained
from Meadwestvaco of Glenn Allen, Va. was tested for comparison.
Measurements were recorded over a 50 hour time period after introduction
of ethyl mercaptan into a sample vial containing either the modified
silica particles of Example 2, the modified silica particles of Example
3, or the activated carbon. The results are shown in FIG. 5.

[0133]From these results, it can be seen that the metal-modified silica
particles remove odorous compounds via a catalytic mechanism when the
modified particles are prepared without the presence of ultrasonic
energy, as the performance of these particles increases over time until
the saturation point of the instrument is reached. The removal of odorous
compounds by metal-modified silica particles prepared in the presence of
ultrasonic energy, however, appears to level off before reaching the
detection limit. The plateau-effect of the particles prepared in the
presence of ultrasonic energy suggests that the saturation of contact
points for the odor compound to bind has been reached.

EXAMPLE 6

[0134]Distinct mechanisms by which copper modified silica particles
prepared with and without ultrasonic energy remediate ethyl mercaptan,
respectively, were demonstrated. The modified silica particles of Example
2 and Example 3 were tested for ethyl mercaptan remediation as described
using Headspace Gas Chromatography with variable temperature over time.
The GC oven was programmed from 30° C.-250° C. (held at
30° C. for 5 minutes, then ramped to 250° C. at 15°
C./min, held at 250° C. for 4 minutes). In addition, activated
carbon (obtained from Meadwestvaco of Glenn Allen, Va.) was tested for
comparison purpose. Measurement was recorded approximately 3 hours after
introduction of ethyl mercaptan into the sample vial. The results are
shown in FIG. 6 in terms of peak area (arbitrary units) and retention
time. The peak at approximately 3.5 minutes represents EtSH, while the
peak at approximately 13.5 minutes represents the disulfide derivative
(EtSSEt) of EtSH.

EXAMPLE 7

[0135]Identification of the disulfide derivative conversion product by the
modified silica particles from Example 2 was demonstrated. The modified
silica particles from Example 2 and Example 3 assessed for ethyl
mercaptan remediation using headspace gas chromatography coupled with
mass spectroscopy. An Agilent Technologies 5973N GC/MS with a 6890 gas
chromatograph was used to analyze the samples. The samples were analyzed
on a J&W DB-5MS capillary column (60 m×0.25 mm×0.25 u film)
using split injection (100:1 split at 225° C.). The GC oven was
programmed from 50° C. (held for 2 minutes) to 300° C. at
25° C./min. Mass spectra were acquired with ionization energy of
70 eV scanning from 35-250 Da at 3.39 spectra/second. Data was collected
and analyzed with ChemStation software supplied with the instrument. The
20 ml headspace vials were sealed with PTFE/Silicone/PTFE septa, and the
gas samples collected with a 25 μl Valco Precision Series A-2 sampling
syringe. The results are shown in FIGS. 7A and 7B in terms of mass-to
charge ratio (M/Z). The mass spectrum (A) corresponds to the GC peak at
approximately 3.5 minutes (r.t.) and exhibits an M/Z 62, which is
identified as ethyl mercaptan. The mass spectrum (B) corresponds to the
GC peak at approximately 13.5 minutes (r.t.) and exhibits an M/Z 122,
which is identified as diethyl disulfide.

EXAMPLE 8

[0136]Identification of two distinct copper species on copper-modified
silica particles from Example 2 and Example 3, respectively, was
demonstrated. Electron paramagnetic resonance (EPR) spectroscopy was used
to identify the nature of the copper species on copper-modified silica
particles from Example 2 and Example 3. The EPR spectrum A in FIG. 8A
corresponds to copper-modified silica particles from Example 2; the
asymmetric spectrum suggests the presence of both isolated and clustered
copper species. The EPR spectrum B in FIG. 8B corresponds to
copper-modified silica particles from Example 3; the relatively symmetric
spectrum suggests the presence of predominantly isolated copper species.

[0138]X-ray photoelectron spectroscopy (XPS) was performed on copper
modified silica particles from Example 2 (CuOXS-2) and copper modified
silica particles from Example 3 (CuOXS-3) for identifying the chemical
nature of copper species. XPS spectra are presented in FIG. 9A and FIG.
9B. Each spectrum was shifted to match the adventitious carbon peak
(284.8 eV). In both the samples important elements were analyzed for
their chemical origin and are tabulated in Table 4.

[0139]XPS spectra of CuOXS-1 sample shows several peaks related to copper
compounds. However, only one peak could be identified and is related to
CuCl2 (from NIST database). CuOXS-2 sample spectra do not have peaks
related to copper. The absence of Cu peak in the XPS spectra could be due
to some coating on the particles surface. Since XPS probes only few
atomic surface layers, copper species coated with some organic/inorganic
layer will be difficult to identify using this technique.

[0141]The data from Examples 6-11 strongly demonstrates the compositional
differentiation of copper modified silica particles from Example 2 and
Example 3 and how each, respectively, remediates ethyl mercaptan
differently. Example 6 and Example 7 are gas chromatography-headspace and
gas chromatography-headspace coupled with mass spectrometry experiments.
The data shows the conversion of ethyl mercaptan to its disulfide
derivative diethyl disulfide by copper modified silica particles from
Example 2. This reaction mechanism is, therefore, catalytic in nature;
and those skilled in the art should be able to recognize the reaction
mechanism applies to odorous compounds with similar redox potential.
Examples of such compounds include organic compounds with aldehyde and
acid functional groups. For copper modified silica particles from Example
3, the data shows a chemical absorption mechanism with evidence of
auto-oxidation of a low concentration of ethyl mercaptan to its disulfide
derivative. Those skilled in the art should recognize the tendency of
sulfide containing compounds to auto-oxidate under ambient conditions.
Additionally, data from Example 6 demonstrates evidence of such
auto-oxidation in test samples not containing copper modified silica
particles.

[0142]Data from Example 8 demonstrates the unique difference in the copper
species in copper modified silica particles from Example 2 and Example 3,
respectively. The electron paramagnetic spectroscopic (EPR) spectrum for
copper modified silica particles from Example 2 is asymmetric, which
suggests the nature of the copper species is clustered. The EPR spectrum
for copper modified silica particles from Example 3 is more symmetric,
which suggests the presence of dominantly isolated copper species. Those
skilled in the art should recognize the difference in EPR spectra
strongly suggests two unique and different copper species in copper
modified silica particles from Example 2 and Example 3.

[0143]Example 9 demonstrates the presence of copper in copper modified
silica particles from Example 2 and Example 3 at comparable
concentration. Data from Example 10 demonstrates that, despite the
presence of copper (data from Example 9), the orientation and positioning
of copper species on the silica surface in copper modified silica
particles from Example 2 and Example 3 are distinct and different.

[0144]In Example 10, the nature of the characterization technique analyzes
for copper at the top 100 nanometer layer of the material. No presence of
copper was detected for copper modified silica particles from Example 3,
while copper was detected for copper modified silica particles from
Example 2. This difference, combined with data from Example 9
demonstrating the comparable presence of copper in copper modified silica
particles from Example 2 and Example 3, strongly suggests the copper
species are different, respectively.

[0145]Data in Example 11 demonstrates a higher concentration of pore
volume in copper modified silica particles from Example 3 compared to
Example 2. This data suggests the trigger for the unique composition in
copper modified silica particles from Example 3 may be due to a
cavitation mechanism enabled by use of ultrasonic energy. The cavitation,
thereby, allows for copper to be deposited onto the silica surface in a
manner that favors isolated copper species; consequently, this unique
composition of copper modified silica particles remediate ethyl mercaptan
differently than copper modified silica particles from Example 2.

[0146]When introducing elements of the present disclosure or preferred
embodiments thereof, the articles "a", "an", "the", and "said" are
intended to mean that there are one or more of the elements. The terms
"comprising", "including", and "having" are intended to be inclusive and
mean that there may be additional elements other than the listed
elements.

[0147]As various changes could be made in the above constructions and
methods without departing from the scope of the invention, it is intended
that all matter contained in the above description and shown in the
accompanying drawings shall be interpreted as illustrative and not in a
limiting sense.